This invention relates to fireplaces and more particularly to a fireplace which vents externally and has a construction which permits use of larger log sets and is less expensive to produce than prior art constructions.
Gas burning log sets having artificial logs which are either placed within an unvented fireplace or an unvented fireplace insert are today very popular since the burning gas supplies a very high heat level, e.g., in the order of 40,000 BTU, efficiently. Substantially all of the gas is burned cleanly and the burning efficiency is very high while the carbon monoxide and carbon dioxide generated generally does not exceed acceptable limits. Such a fireplace wherein the combustion products need not be vented outside the building and may be directed into the room to heat the room is disclosed in the aforesaid application. The fireplace in which the burning log set is installed may be a conventional wood burning fireplace with the exhaust flue closed or may be a direct vent fireplace, i.e., that where the combustion products whether artificial or wood, are vented to the exterior of the building. These vented fireplaces generally have multiple spaced apart sheet metal walls welded or otherwise connected together. One such fireplace of this type is illustrated in Shimek et al. U.S. Pat. No. 5,263,471. The multiple wall construction limits the actual log receiving space for fireplaces of given outside dimensions since the space between such walls causes a reduction in the width of the log receiving space. This is true whether the logs are wood or artificial. Additionally, fireplaces with this construction have a relatively expensive manufacturing cost, for various reasons, not the least of which is the amount of sheet metal required and the necessity of connecting the various walls together, the latter generally being done by welding.
In the aforesaid patent application an unvented fireplace construction is disclosed wherein a solution to this problem is proposed having ceramic refractory abutting the sheet metal sides of the fireplace and a ceramic refractory spaced for the sheet metal at the rear. Until now it has not been recognized that this structural concept may be applied to fireplaces which vent externally of the room in which the fireplace is mounted.